A life taken seriously every minute becomes difficult to enjoy sincerely.

Total seriousness makes a life hard to be inside. Everything becomes weighted, every decision heavy, every failing significant. The people who seem to be enjoying themselves are not less serious about what matters; they have simply stopped applying that intensity to everything indiscriminately.

Look for a place where you could take something less seriously without any actual cost. A hobby you are grim about, a standard nobody asked for. Lightening one of those changes the atmosphere more than you would expect.